changing oil filters ford cargo 813?

Not sure what you mean when you say 'my lorry air locker' If you mean its air locked then ive never heard of an oil system air locking, you just unscrew the filters fit new and hand tighten, run the engine with new oil untill the oil light goes out usually 10-15 secs max, stop engine top up oil to max mark, re-run engine and check for leaks.

DB Transport
March 2011